Multiprotocol Label Switching (MPLS) enables efficient delivery of a wide variety of differentiated, end to end services. Multiprotocol Label Switching (MPLS) traffic engineering (TE) provides a mechanism for selecting efficient paths across an MPLS network based on bandwidth considerations and administrative rules.
In current implementations of Multicast Virtual Private Networks (MVPN) with Resource Reservation Protocol (RSVP) Point-to-Multipoint (P2MP), switching from Inclusive Provider Multicast Service Interface (I-PMSI) to Selective Provider Multicast Service Interface (S-PMSI) typically happens after a predefined switch-over delay interval (S-PMSI_DELAY as described in Internet Engineering Task Force (IETF) Request for Comment (RFC) 6513, hereby incorporated by reference) which does not ensure that all Source-to-Leaf (S2L) paths in the S-PMSI P2MP LSP are up before the switchover. This can lead to traffic loss for receiving Provider Edge (PE) routers having S2L paths which took a longer time to establish than the switch-over delay interval.
Secondly, if S-PMSI configuration is enabled then new S-PMSI P2MP LSPs will be signaled if all PE routers participating in the MVPN have active receivers. This causes extra states in the network core with no bandwidth conservation, which is generally considered the purpose of S-PMSI.
Therefore, improvements to management of S-PMSI resources are highly desirable.